检索结果-南通市图书馆

International Journal of Minerals,Metallurgy and Materials 2021年第1期28卷 131-141页

作者： gao-hui li li Zhou ling-yun Luo Xi-ming Wu Ning Guo State Key Laboratory of Advanced Welding and Joining Harbin Institute of TechnologyHarbin 150001China Shandong Provincial Key Laboratory of Special Welding Technology Harbin Institute of Technology(WeihaiWeihai)264209China

In this study, we used the stop-action technique to experimentally investigate the material flow and microstructural evolution of alclad 2A12-T4 aluminum alloy during refill friction stir spot *** are two material flow components, i.e., the inward-or outward-directed spiral flow on the horizontal plane and the upward-or downward-directed flow on the vertical *** the plunge stage, the flow of plasticized metal into the cavity is similar to that of a stack, whereby the upper layer is pushed upward by the lower *** the refill stage, this is process *** such, there is no obvious vertical plasticized metal flow between adjacent *** leads to the coarsening of S(Al2CuMg) in the thermo-mechanically affected zone and the diminishing of S in the stir *** dynamic recrystallization results in the formation of fine equiaxed grains in the stir zone, but this process becomes difficult in the thermo-mechanically affected zone due to the lower deformation rate and the pinning action of S precipitates on the dislocations and sub-grain boundaries, which leads to a high fraction of low-angle grain boundaries in this zone.

关键词： refill friction stir spot welding aluminum alloy material flow behavior precipitate evolution dislocation configuration

Effect of tool plunge depth on the microstructure and fracture behavior of refill friction stir spot welded AZ91 magnesium alloy joints

在线全文

学校读者我要写书评

暂无评论

International Journal of Minerals,Metallurgy and Materials 2021年第4期28卷 699-709页

作者： Hai-feng Zhang li Zhou Wen-lin li gao-hui li Yi-tang Tang Ning Guo Ji-cai Feng Shandong Provincial Key Laboratory of Special Welding Technology Harbin Institute of Technology at WeihaiWeihai 264209China State Key Laboratory of Advanced Welding and Joining Harbin Institute of TechnologyHarbin 150001China

We used refill friction stir spot welding(RFSSW)to join 2-mm-thick AZ91D-H24 magnesium alloy sheets,and we investigated in detail the effect of tool plunge depth on the microstructure and fracture behavior of the joints.A sound joint surface can be obtained using plunge depths of 2.0 and 2.5 *** depth was found to significantly affect the height of the hook,with greater plunge depths corresponding to more severe upward bending of the hook,which compromised the tensile-shear properties of the *** hardness reached a minimum at the thermo-mechanically affected zone due to the precipitation phases of this zone as it dissolved into theα-matrix during the welding *** fracture modes of RFSSW joints can be divided into three types:shear fracture,plug fracture,and shear–plug *** these,the joint with a shear–plug fracture exhibited the best tensile-shear load of 6400 N.

关键词： refill friction stir spot welding AZ91 magnesium alloy microstructure fracture behavior

Difference schemes on non-uniform mesh and their application

在线全文

学校读者我要写书评

暂无评论

Progress in Natural Science:Materials International 2004年第10期14卷 8-14页

作者： MA Yanwen ,gao hui,FU Dexun and li Xinliang (Laboratory of Nonlinear Mechanics,Institute of Mechanics,Chinese Academy of Sciences,Beijing100080,China) Chinese Acad Sci Inst Mech Lab Nonlinear Mech Beijing 100080 Peoples R China

High order accurate schemes are needed to simulate the multi-scale complex flow fields to get fine structures in simula-tion of the complex flows with large gradient of fluid parameters near the wall,and schemes on non-uniform mesh are desirable for many CFD(computational fluid dynamics)*** construction methods of difference approximations and several difference approxima-tions on non-uniform mesh are *** accuracy of the methods and the influence of stretch ratio of the neighbor mesh increment on accuracy are *** comments on these methods are given,and comparison of the accuracy of the results obtained by schemes based on both non-uniform mesh and coordinate transformation is made,and some numerical examples with non-uniform mesh are present-ed.

关键词： scheme on non-uniform mesh high order accurate scheme compact difference approximation

Differences and Correlations of Morphological and Hemodynamic Parameters between Anterior Circulation Bifurcation and Side-wall Aneurysms

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Current Medical Science 2024年第2期44卷 391-398页

作者： Kai-kai GUO Chang-ya liU gao-hui li Jian-ping XIANG Xiao-chang LENG Yi-ke CAI Xue-bin HU Department of Neurosurgery Union HospitalTongji Medical CollegeHuazhong University of Science and TechnologyWuhan 430022China Department of Emergency Longhua HospitalShanghai University of Traditional Chinese MedicineShanghai 200032China Artery Flow Technology Co. Ltd.Hangzhou 310051China

Objective:The objective of this research was to explore the difference and correlation of the morphological and hemodynamic features between sidewall and bifurcation aneurysms in anterior circulation arteries,utilizing computational fluid dynamics as a tool for ***:In line with the designated inclusion criteria,this study covered 160 aneurysms identified in 131 patients who received treatment at Union Hospital of Tongji Medical College,Huazhong University of Science and Technology,China,from January 2021 to September *** follow-up digital subtraction angiography(DSA)data,these cases were classified into two distinct groups:the sidewall aneurysm group and the bifurcation aneurysm *** and hemodynamic parameters in the immediate preoperative period were meticulously calculated and examined in both groups using a three-dimensional DSA reconstruction ***:No significant differences were found in the morphological or hemodynamic parameters of bifurcation aneurysms at varied locations within the anterior ***,pronounced differences were identified between sidewall and bifurcation aneurysms in terms of morphological parameters such as the diameter of the parent vessel(Dvessel),inflow angle(θF),and size ratio(SR),as well as the hemodynamic parameter of inflow concentration index(ICI)(P0.5,P<0.001).Conclusions:The significant differences in certain morphological and hemodynamic parameters between sidewall and bifurcation aneurysms emphasize the importance to contemplate variances in threshold values for these parameters when evaluating the risk of rupture in anterior circulation *** it is a bifurcation or sidewall aneurysm,these disparities should be *** morphological parameter SR has the potential to be a val

关键词： sidewall bifurcation unruptured aneurysms computational fluid dynamics

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

自噬与糖尿病肾病相关性研究进展

国际药学研究杂志 2016年第5期43卷 844-848,857页

作者：郑元慧高丽辉李玲昆明医科大学生物医学工程研究中心昆明650500

自噬是细胞为应对内外环境压力变化而出现的一种正常反应,是细胞内物质成分被溶酶体降解的过程。近年来研究发现,自噬在糖尿病肾病(DN)的发生发展中起着重要作用,是DN治疗的潜在靶点,与肾足细胞的生长发育和生理病理活动密切相关,是一... 详细信息

自噬是细胞为应对内外环境压力变化而出现的一种正常反应,是细胞内物质成分被溶酶体降解的过程。近年来研究发现,自噬在糖尿病肾病(DN)的发生发展中起着重要作用,是DN治疗的潜在靶点,与肾足细胞的生长发育和生理病理活动密切相关,是一种细胞的自我保护机制,调控自噬相关信号通路可影响DN发生发展。因此,本文就DN的发病机制、自噬在肾固有细胞中的作用以及调控自噬相关信号通路对糖尿病肾病发生发展的影响等方面进行综述。

关键词：糖尿病肾病自噬通路肾脏足细胞

Real-world evidence on the efficacy and safety of vonoprazanamoxicillin dual therapy for Helicobacter pylori treatment in elderly patients

在线全文

学校读者我要写书评

暂无评论

World Journal of Gastroenterology 2025年第1期31卷 68-78页

作者： Wen gao Jing-Wen li hui Ye Xue-Zhi Zhang Jian-Xiang liu Hong Cheng Department of Gastroenterology Peking University First HospitalBeijing 100034China School of Medicine Tsinghua MedicineTsinghua UniversityBeijing 100034China Department of Traditional Chinese Medicine and Integrative Medicine Peking University First HospitalBeijing 100034China

BACKGROUND A dual therapy regimen containing amoxicillin is a common treatment option for the eradication of Helicobacter pylori(***).While substantial research supports the efficacy and safety of vonoprazan and amoxicillin(VA)dual therapy in the general population,there is still a lack of studies specifically focusing on its safety in elderly *** To evaluate efficacy and safety of VA dual therapy as first-line or rescue treatment for *** in elderly *** As a real-world retrospective study,data were collected from elderly patients aged 60 years and above who accepted VA dual therapy(vonoprazan 20 mg twice daily+amoxicillin 1000 mg thrice daily for 14 days)for *** eradication in the Department of Gastroenterology at Peking University First Hospital between June 2020 and January *** status was evaluated by^(13)C-urease breath test 6 weeks after *** adverse events(AEs)during treatment were *** In total,401 cases were ***-one cases were excluded due to loss to follow-up,lack of re-examination,or unwillingness to take *** total of 380 included cases comprised 250 who received VA dual therapy as first-line treatment and 130 who received VA dual therapy as rescue *** was successfully eradicated in 239 cases(95.6%)in the first-line treatment group and 116 cases(89.2%)in the rescue treatment *** overall incidence of AEs was 9.5%for both ***,9.2%of patients experienced an AE in the first-line treatment group and 10.0%in the rescue treatment *** patients discontinued treatment due to AE,with a discontinuation rate of 1.3%.No serious AE *** The VA dual therapy regimen as a first-line treatment and a rescue therapy was effective and safe for elderly patients aged 60 and older.

关键词： Helicobacter pylori Vonoprazan Amoxicillin Dual therapy Elderly

Mechanisms of improvement of left ventricle remodeling by transplanting two kinds of autologous bone marrow stem cells in pigs

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Medical Journal 2008年第23期121卷 2403-2409页

作者： li Shu-ren QI Xiao-yong HU Fu-li ZHANG Jian-qing WANG Tian-hong DANG Yi MENG Cun-liang liU hui-liang li Ying-xiao WU Di DONG Jie XUN li-ying gao li-hui JIN Fu-chang Department of Cardiology People's Hospital of Hebei Province Shijiazhuang Hebei 050051 China

Background The necrosis of a large number of myocardial cells after acute myocardial infarction （AMI） results in a decrease of cardiac function and ventricle remodeling. Stem cell transplantation could improve cardiac function after AMI, but the involving mechanisms have not been completely understood. The present study aimed to investigate the effects of transplantation of autologous bone marrow mononuclear cells （BM-MNC） and mesenchymal stem cells （MSCs） via the coronary artery on the ventricle remodeling after AMI as well as the mechanisms of the effects of transplantation of different stem cells on ventricle remodeling. Methods A total of 36 male pigs were enrolled in this study, which were divided into 4 groups： control group, simple infarct model group, BM-MNC transplantation group, and MSCs transplantation group. At 90 minutes when a miniature porcine model with AMI was established, transplantation of autologous BM-MNC （（4.7±1.7）×10^7） and MSCs （（6.2±1.6）×10^5） was performed in the coronary artery via a catheter. Ultrasound, electron microscope, immunohistochemical examination and real time reverse transcriptase-pelymerase chain reaction were used respectively to observe cardiac functions, counts of blood vessels of cardiac muscle, cardiac muscle nuclear factor （NF）-κB, myocardial cell apoptosis, and the expression of the mRNA of vascular endothelial growth factor （VEGF） and basic fibroblast growth factor （bFGF） in cardiac muscles. Multivariate Logistic regression was used to analyze the correlation factors of left ventricular end-diastolic diameter （EDD）. Results The number of blood vessels in the infarct zone and around its border in the BM-MNC transplantation group was more than those in the infarct model group and MSCs group （P=0.0001） and there was less myocardial cell apoptosis in the stem cell transplantation group than that in the infarct model group （all P 〈0.01）. The positive rate of NF-κB in the stem cell transplantation group was lower than th

关键词： bone marrow mononuclear cell bone marrow mesenchymal stem cell cellular transplantation acute myocardial infarction ventricle remodeling

Local magnetic moment oscillation around an Anderson impurity on graphene

在线全文

学校读者我要写书评

暂无评论

Science China(Physics,Mechanics & Astronomy) 2025年第1期Mechanics & Astronomy) .卷 192-201页

作者： Shuai li Zhen Ma Jin-Hua gao School of Science Hebei University of Science and Technology School of Electronics and Information Zhengzhou University of Light Industry School of Physics and Wuhan National High Magnetic Field Center Huazhong University of Science and Technology

We theoretically investigate the spin resolved Friedel oscillation （FO） and quasiparticle interference （QPI） in graphene induced by an Anderson *** the impurity becomes magnetic,the resulted FO becomes spin dependent,which gives rise to a local magnetic moment oscillation with an envelop decaying as r-2in real space in the doping ***,at half filling,the electron density and local magnetic moment will not oscillate but decay as *** spin resolved FO has both sublattice and spin ***,the local magnetic moment decay at half filling only occurs at one sublattice of graphene,which is quite like the phenomenon observed in the STM experiment (***ález-Herrero et al.,Science 352,437 （2016）).We further give an analytic formula about such spin dependent FO based on the stationary phase ***,we study the interference of quasiparticles around the magnetic impurity by calculating the spin dependent Fourier-transformed local density of states （FT-LDOS）.Our work gives a comprehensive understanding about the local magnetic moment oscillation around an Anderson impurity on graphene.

关键词： Friedel oscillation local magnetic moment graphene Anderson impurity

互联网+背景下少数民族地区远程开放教育课程辅导教师专业能力培养

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

内蒙古师范大学学报（自然科学汉文版） 2017年第3期46卷 390-393页

作者：高卉李晶内蒙古广播电视大学内蒙古呼和浩特010011 内蒙古财经大学经济管理实验实训中心内蒙古呼和浩特010070

阐述了互联网+背景下远程开放教育课程辅导教师所面对的挑战与职能转变,在分析其能力提升重要性的基础上,从加强团队建设、专业培训引领、注意民族文化的学习和融合等方面,提出了远程开放教育课程辅导教师专业能力提升的途径.

关键词：互联网+ 少数民族地区远程开放教育课程辅导教师专业能力成长

14 nm工艺下基于H-Tree和clock mesh混合时钟树的研究与实现

在线全文

学校读者我要写书评

暂无评论

电子技术应用 2017年第11期43卷 34-37,42页

作者：高华李辉中国科学技术大学信息科学技术学院安徽合肥230026

在数字集成电路设计中,时钟信号是数据传输的基准,时钟信号作为数字芯片内部转换频率最高和布线距离最长的信号,也是数字芯片功耗的重要组成部分。为了优化数字芯片的功耗、功能和稳定性,在GF14 nm工艺下对时钟树进行优化设计,提出一种H... 详细信息

在数字集成电路设计中,时钟信号是数据传输的基准,时钟信号作为数字芯片内部转换频率最高和布线距离最长的信号,也是数字芯片功耗的重要组成部分。为了优化数字芯片的功耗、功能和稳定性,在GF14 nm工艺下对时钟树进行优化设计,提出一种H-Tree和clock mesh相结合的混合时钟树结构的设计方法,通过clock mesh和clock spine的布局优化整体时钟树的性能和稳定性。仿真结果表明,该混合时钟树能够结构显著提升时钟树性能,有效减少布线长度、时钟偏移以及传播延迟,降低PVT等环境参数的影响。

关键词： 14 nm 时钟树综合 clock mesh H-Tree